1. Field of the Invention
The present invention relates to technology for improving the productivity of an active matrix liquid crystal device. The present invention relates to technology of injecting a liquid crystal material into a panel forming a liquid crystal device.
2. Description of the Related Art
Generally, when an active matrix liquid crystal device is manufactured, the process of injecting a liquid crystal material into a panel forming the liquid crystal device utilizes vacuum injection. Vacuum injection is a method of injecting a liquid crystal material utilizing capillarity and difference in pressure. A general method of filling a panel with a liquid crystal material according to vacuum injection is described as follows.
It is to be noted that, in the present specification, an element substrate means a substrate provided with an active matrix circuit and peripheral driver circuits thereon. A counter substrate means a substrate which is provided so as to face an element substrate and on which counter electrodes, a color filter, and so on are formed.
FIG. 5 shows a conventional process of injecting a liquid crystal material. In FIG. 5, an element substrate 505 and a counter substrate 506 of a panel 501 are provided so as to face each other interposed a sealing material 504 therebetween.
The element substrate 505 has a pixel region 502 of an active matrix structure and peripheral driver circuit regions 503 provided with a circuit for driving the pixel region. The peripheral driver circuits provided on the element substrate 505 may be directly formed on a glass substrate, or, alternatively, may be formed by sticking an IC chip later.
On the other hand, the counter substrate 506 is provided with color filters and counter electrodes both of which face the pixel region 502 but are not shown.
Except for an injection hole 510 for the liquid crystal material, the sealing material 504 is provided so as to surround the pixel region 502. Here, the size of the counter substrate 506 is large enough to cover the region where the sealing material 504 is provided. The sealing material 504 is provided between the pixel region 502 and the peripheral driver circuit regions 503. The peripheral driver circuit regions 503 are provided outside the region occupied by the counter substrate 506.
A single or a plurality of the injection holes 510 for the liquid crystal material are provided on a side among the peripheral portion of the panel 501 where the end faces of the pair of substrates 505 and 506 are aligned.
The panel 501 is arranged inside a vacuum chamber 521. In FIG. 5, the panel 501 is supported by a holder which is not shown. Here, the panel 501 is perpendicularly disposed so that the injection hole 510 comes to the bottom.
In order to improve the productivity, batch processing is often carried out with a plurality of panels being disposed inside the vacuum chamber at a time.
The vacuum chamber 521 has an evacuation pipe 523 connected therewith through a valve 522. The evacuation pipe 523 is connected with a vacuum pump which is not shown to enable the pressure inside the vacuum chamber 521 to be reduced.
Further, a liquid crystal vessel 525 containing a liquid crystal material 524 is disposed on a stage 526. The stage 526 is vertically movable.
After the panel 501 is disposed, the air inside the vacuum chamber 521 is evacuated from the evacuation pipe 523 so that the pressure inside the vacuum chamber 521 is reduced to be on the order of 1.times.10.sup.-5 Torr.
Next, the stage 526 is moved up to soak the injection hole 510 in the liquid crystal material 524 in the liquid crystal vessel 525. Here, both of the liquid crystal vessel 525 and the panel 501 are often heated to enhance the flowability of the liquid crystal material 524.
With the above state being maintained, by gradually raising the pressure inside the vacuum chamber 521, due to the difference in pressure and capillarity, the liquid crystal material 524 is injected into the panel 501 as shown by an arrow in FIG. 5.
Next, the valve 522 is released to terminate the state of the reduced pressure, and the panel 501 with the liquid crystal material 524 injected therein is taken out from the vacuum chamber 521.
Thereafter, both sides of the panel are pressurized to extrude excess liquid crystal, and, with the state maintained, ultraviolet curing or heat curing resin for sealing is applied to the injection hole 510, and then, the pressurization is removed. Then, the resin for sealing comes a little in the inside of the injection hole. With the state maintained, the resin for sealing is cured to seal the injection hole 510. In this way, the process of injecting the liquid crystal material is completed.
With the process of injecting the liquid crystal material according to vacuum injection, with respect to every panel or every batch, the processes of carrying the panel into the vacuum chamber, reducing the pressure, injecting the liquid crystal material, terminating the state of the reduced pressure, and taking out the panel are required to be repeated.
Among these processes, the injection of the liquid crystal material often takes an hour to more than several hours, even with respect to a panel having a diagonal on the order of 10 inches long thereof.
Particularly, recently, as a method of manufacturing a liquid crystal device of high productivity, a method referred to as "multiple" has become the mainstream. This is a method in which plural sets of a pixel region and peripheral driver circuit region that constitute one panel are formed on one substrate, a large panel (multiple panel) is formed by sticking a counter substrate with a sealing material, and thereafter, the large panel is separated into individual panels.
However, even in this method, injection of the liquid crystal material into the panel is conducted after separating the large panel into individual panels. Thus, when the liquid crystal material is injected into the respective panels, for example, in case four panels are taken (from one multiple panel, four panels each of which constitutes a liquid crystal device are to be obtained), the multiple panel is separated into four panels, and, injection of the liquid crystal is carried out separately with respect to the respective panels, and thus, the process of injecting is required to be repeated four times, which prevents the time necessary for the manufacturing process from being shortened.
Therefore, in order to improve the productivity of a liquid crystal device, the time necessary for the process of injecting the liquid crystal material is required to be shortened.